Mount MySQL tmpdir as tmpfs for better performance

1. Create a directory
   #mkdir -p /var/mysqltmp
2. Change directory ownership to mysql user
   chown mysql:mysql /var/mysqltmp 
3. Get uid and gid of mysql user
   #id mysql 
4. Edit /etc/fstab to automatically mount tmpfs, add a new line. replace gid and uid
   tmpfs /var/mysqltmp tmpfs rw,gid=27,uid=27,size=2G,nr_inodes=50k,mode=0700 0 0 
5. Mount the filesystems as defined in /etc/fstab
   mount -a 
6. Edit /etc/my.cnf to change  tmpdir
   [mysqld]
   tmpdir = /var/mysqltmp 
7. Restart mysqld service
   #service mysqld restart 
8. Check if variable is updated in mysql console
   SHOW VARIABLES LIKE 'tmpdir';